Balance sheet components (Details 5) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Finite Lived Intangible Assets [Line Items]
Gross Assets	$ 55,111	$ 50,996
Accumulated Amortization	(43,942)	(40,733)
Net Assets	11,169	10,263
Technology and patents
Finite Lived Intangible Assets [Line Items]
Gross Assets	37,685	34,023
Accumulated Amortization	(30,474)	(28,402)
Net Assets	7,211	5,621
Customer relationships
Finite Lived Intangible Assets [Line Items]
Gross Assets	15,226	14,725
Accumulated Amortization	(12,300)	(11,176)
Net Assets	2,926	3,549
Leasehold interest
Finite Lived Intangible Assets [Line Items]
Gross Assets	1,338	1,386
Accumulated Amortization	(306)	(293)
Net Assets	1,032	1,093
Non-compete agreements
Finite Lived Intangible Assets [Line Items]
Gross Assets	862	862
Accumulated Amortization	$ (862)	$ (862)